Apparatus for printing photographs from negatives



Oct. 5 1926. 1,602,051

1. D. SHARP APPARATUS FOR PRINTING PHOTOGRAPHS FROM NEGATIVES Filed May 23, 1923 2 Sheets-Sheet 1 WITNESSES IN V EN TOR Wm jwfl Sim/2 v. 7 k5,

A TTORNE YS Patented Oct. 5, 1926.

UNITED STATES IRA D. SHARP, OF NICHOLASVILLE, KENTUCKY.

APPARATUS FOR PRINTING PHOTOGRAPHS FROM NEGATIVES.

Application filed May 23, 1923.

This invention relates to an apparatus for the printing of photographs from negatives and more particularly to that type of printing machine described and claimed in my Patent No. 1,521,399, dated December 30, 1924;.

An object of the invention is the provision of a device for printing photographs in which the intensity of the light may be varied according to the density of the negatives and in which the time of exposure remains constant for photographic papers of constant speed.

A further object of the invention is the provision of a device for printing photographs having an automatically controlled time element for operating a switch of an electric circuit to close and open the circuit whereby the proper exposure may be had and the time of exposure be limited to a definite period of time or the time element may be so controlled for varying the period of exposure according to the sensitiveness of the paper.

Another object of the invention is the provision ofa compact and.unitary structure for printing photographs in which the intensity of the light may be accurately varied according to the density of the negatives and the speed of the paper and in which the operation of the light and time of exposure is controlled by the operation of an element connected with the usual platen.

A still further object of the invention is the provision of a unitary and compact device for printing photographs in which the operation of the platen causes the actuation of a time element for determining the period of exposure of the printing paper, the time clement automatically operating a switch for closing a circuit and the switch and time element being so constructed that either one may be removed without disturbing the other element.

Other objects and advantages will become apparent during the course of the following description.

The invention is illustrated by Way of example in the accompanying drawings, in which:

Figure 1 is a View in perspective of the apparatus for the printing of photographic prints from negatives.

Serial No. 640,955.

Figure 2 is a vertical longitudinal section of the printing apparatus.

Figure 3 is a diagrammatic representation of the wiring.

Referring to the drawings, 1 designates a table having an inclined portion 2 and supported by pairs of legs 8. The main body of the table is adapted to be located horizontally. The inclined portion 2 of the table is provided with an opening 4: which is covered by a transparent member 5 upon which is adapted to be placed the negative to be printed. Secured to the bottom portion of the member 2 of the table and embracing the opening 4 is a casing 6 forming a housing for the lamp 7 and a reflector for the light to be projected through the negative located on the transparent member 5. Any form of reflectors may be employed within the casing 6. While I have shown one lamp 7 any number of lamps may be employed as may be desired. A red lamp 8 is disclosed in circuit with the house current for illuminating the interior for working purposes of the apparatus.

A horizontal block 9 is secured to the table top and upon which is hingedly mounted a platen 10 at 11. Secured to the outer end of the platen 10 is a block 12 provided on its outer face with any form of felt or other material in order to firmly and evenly press the paper and negative into close contact with each other and with the glass printing surface. Hingedly mounted upon the outer end of the platen 10 at 13 is a second block 14 likewiseprovided with felt 20 or other suitable material similar to the material disposed upon the outer face of the block 12 An operating lever 21 is hingedly moun ed upon the hinge pin 11 and is adapted to be operated within a slot 22 formed in the platen 10. Springs 23 and 24 connect the lever 21 respectively to the platen 10 and the block 1 so that when the lever 21 is operated the platen will likewise be moved simultaneously therewith. A guide rod 25 secured to the lever 21 operates in a perforation in the platen 10 for maintaining the arm in proper relation with said platen. A lug 26 is secured to the inner end of the lever 21 for a purpose which will be presently described.

Spaced journals 27 are mounted upon the able 1 upon opposite sides of the s t L8 and are adapted to support a pivot pin L9. Pivotally mounted on the pin 2. is a pendulum 30 which passes through the L8 and is provided with adjustable \vei; 31 and for varying the time of ()SClllZlilUl. ot

nected to the lite- 26 on the lever 21 and its other end connected to a hook 2-3? mounted on the adjustable sleeve -ne lever 33 an... is adapted to in its mos rea upon the stop lever at on end to the stop other end to a post 40 tain the stop lever o3 position inclined at at angle to the t: the position shown in Figure ,L.

A swine'ahle lever ll pivoted upon pin 29 is ada'ited to be locked at end to the up er end of the pen by means of a l itsoaped colla e ured o "l i i l L1G peneituin.

Pro ecting at an ang e to the lover a knife switch member 43 which is adao to have timed engagements with a U-sha contact i1- during the operation of the p dulum 30. T he member 4-3 is 1.

l I a I will a conductor which is carried do.

wardlj along the lever 41 but insulated the lever from the pin 29, and is ad to engage a hrush itftormed in the block The brush i6 is electrically connected it the binding post it]. The U-shaped contact H is electrically connected to th post -19.

As shown more particularlv the insulated conductor 50, nected with the binding post i. with the plug 51 which is screwed into the ordinate. socl with the house current. A swi is located atanv pointupon the table 1 for breaking; this circuit. The insulated conductor 53 connects the U-shaped. contact member 49 with one end 5% of :1 rheostet mounted in a asing 55. An arm 56 of the rheostat operated by a thumb piece 56 electriealh connects the wire through the so; ments of the resistance 5? i 58 which leads to the resistance coil 59. resistance coil 59 has a greater range than the smaller rheesta and therefore is more capable of reducing the intensity of the limp 7.

An arm (30 .isadaptcd to more orer the contacts ($1 and in the direction ind':ated b the arrow for decreasin'" he resistance ore providing lfoa .ater intensity of I?! or when the arm (it a: moved in op on indicate-1i h he arrow. the l hqly increased n the (-iore tne inte t. h will he decreased. (1)

1 Figure l as movable over the con- 1 sine 0 whc secured, to the ounted within a cas' ip t hulh cas 6.

the l rom t term a one poses 0t the arm (it) One and a c moved to the contact A .1 u w :1 guarter the resistance is culti- (ientl redn he one and one-ouertar lir'l a itn.

. units. The two units and so on as noted hr the co esponding num ers opposite the WZCCULHJDTT c :ntacts. When th last contact it desie'nzued hv the nu eral strength of the lamp T i and the 111.22 est intone therefore hat.

The smaller rheostet 55 is operated in conjunction with the rheost t 5?) th contact {l ve is reached. the tull not live 0e l is and. divided in tenths as ehr h ttance had by the small 1 is ct; 1'11 to the res stance between anr two of the contacts of the larger rl eo. t so that when the smaller rheostat is open tion with the inner in will be added to the re: rh ostat and ti n the lamp to T he ed in coniuncoperation inv he negative is pl he 'ansturent nienihe t 1 paper is located 11 i 1 members engage tl I h re block 1 1; permits sa'd nlot 2 moved upon its hinge and raised 0 inspection 0:! the ape" th e we in .HTiIlt the .r is col-re posiransnarent member 5. hen

the arm 21 l: l to the dotted line EROXT Hit) lit)

tion the flexible member 36 is made taut as shown in dot-ted lines.

In order to permit the pendulum 30 to operate the lever 21 is depressed against the tension of the springs 23 and 24 and moved in close association with the platen 10. Since the li :rible member has been extended in taut relation by the lowering of the lever 21 and the platen 10, further moverent of said lever will cause said flexible member to move the stop lever forwardly and likewise the arm 35 away from the ijiumper 34 of the pendulum 30. This releases the pendulum and permits the same to swing when the knife contact 43 will move into engagement with the U-shaped contact 44 thereby closing the circuit to lamp '7 and causing an inst-ant flash in said lamp. The lever 21 may be released when the spring 89 will return the stop lever 33 to its normal position and prevent the pendulum 30 from further swinging movement. If it be desired to release the lever to obtain more than one flash, the pendulum 30 may be permitted to swing and make any number of contacts desired between the members 43 and 44.

If it is desired at any time to change the time of oscillation of the pendulum 30, the weights 31 and 32 may be adjusted accorcingly.

If at any time it be desired to disconnect the pendulum 30 from the lever 41 the set screws 67 and 68 may be released from their engagement with the lever 41 whereby the yoke 42 may he removed and thus disconnect the lever 41 from the pendulum 30.

The set screws 67 and 68 may be so adjusted as to mox e the lever 41 slightly out of alinement with the pendulum 30 and change the time of contact between the members 43 and 44, or where the members 43 and 44 do not properly contact at the time desired the set screws 67 and 68 may be adjusted to eiiectthe proper positioning of the lever 41 and thereby correct variations in the time of such contacts.

A spring 70 connected at one end to the lug 26 and at its other end to the hook 71 on the table 1 returns the lever 21 and platen 10 to their normal inoperative position and out of engagement with the inclined portion 2 of the table.

It must be borne in mind that the values of the light intensities assigned to the various contact points shown in Figure 3 are purely arbitrary and are for purposes of illustration only. These values may be varied according to determinations acquired from experiments and such variations may be made without in any way aifecting the scope of the invention.

The printer is shown as having a pair of co-operating coils tapped at regular intervals in order to vary the intensities of the light as desired and where such close adjustment is not required, the small rheostat may be disregarded and the larger coil may be tapped at such intervals as to provide any form of scale of intensities.

The scale oi successive light intensity values may be made to approximate a geometrical progression which permits the use of a sliding or shifting scale to .compensate for variations in the speeds of different makes of papers.

Not only does the speed of the different makes of papers aliect the selection of the proper resistance but the density of the negatives must be taken into consideration, since the amount of light transmitted by a negative is an important factor in the pro duction of good prints. Therefore, the ad justment of the resistanceelement must be correlated in accordance with the transparency of the negative and speed of the paper.

WVhat I claim is:

1. In a printing machine for printing of. photographic prints, an electric circuit, an illuminating device in said circuit, means for supporting a negative and photographic printing paper within effective light exposed relation with the illuminating device, a resistance in said circuit for varying the intensity of the light in accordance with the density of the negative, a movable platen for maintaining the negative and paper in position at the time of exposure, means automatically set in motion upon the operation of the platen for closing and opening the circuit and timing the exposure of the photographic paper in accordance with the speed of the paper, a lever for operating the platen, a resilient means for flexibly connecting the lever to the platen whereby said lever is capable of movement beyond the limits of movement of the platen, and means connecting the timing means with the lever whereby said timing means is set in operation when the lever is moved beyond the limit of movement of the platen.

2. In a printing machine for printing of photographic prints, an electric circuit, an illuminating device in said circuit, means for supporting a negative and photographic printing paper within effective light exposed relation with the illuminating device, a resistance in said circuit for varying the intensity of the light in accordance with the density of the negative, a movable platen for maintaining the negative and paper in position at the time of exposure, means automatically set in motion upon the operation of the platen for closing and opening the circuit and timing the exposure of the photos graphic paper in accordance with the speed of the paper, said platen including a pivoted leaf adapted to be moved independently of the platen and out of engagement with the photographic paper, a lever for operating the platen, and resilient means connecting relation with the illuminating device, a re' sistance in said circuit for varying the intensity ot the light in accordance with the density or the negative, a platen for maintaining the photographic negative and paper in position at the time oi exposure, a lever for operating said platen and capable of movement beyond the limits of movement of the platen, a pendulum adapted to be oscillated for closing and opening the circuit, means for locking the pendulum in an angular position relative to the vertical, means connected with the lever for releasing the locking means from its engagement with the pendulum and adapted to be operated upon the final movement of the lever which is beyond the limits of movement of the platen, said connecting means between the lever and the lockingmeans comprising a flexible elementadapted to be drawn taut at the limit of movement of the platen, said flexible means being adapted to cause movement of the locking means by a subsequent movement of the lever.

IRA D. SHARP. 

